Right Atrial and SVC Cardiac Sarcoidosis: Not All Atrial Masses Are Tumors

Right atrial (RA) masses create diagnostic challenges; extension into surrounding venous structures is rare.

A 56-year-old woman presented with variable heart block and was found to have an RA mass extending into the superior vena cava (SVC). ¹⁸F-fluorodeoxyglucose positron emission tomography demonstrated metabolic activity within the myocardium, mediastinum, and pancreas concerning for sarcoidosis versus neoplasm. Endomyocardial biopsy was inconclusive. Transvenous pacemaker placement was not feasible given partial SVC obstruction by the mass. Ultimately, the patient underwent surgical mass resection, SVC reconstruction, and epicardial pacemaker placement. Final pathology confirmed sarcoidosis.

RA involvement in sarcoidosis is rare, and SVC extension has not been reported. This case highlights the diagnostic challenges associated with this presentation and the importance of a multidisciplinary approach.

Cardiac sarcoidosis may present as a rapidly developing RA mass with rare venous extension, complicating therapeutic options. Multidisciplinary evaluation and management are necessary for treatment.